Process for manufacturing molecular sieve of MFS framework type and its use

ABSTRACT

A method of making a crystalline molecular sieve of MFS framework type, said method comprising the steps of (a) adding at least one source of ions of tetravalent element (Y), at least one source of ions of trivalent element (X), at least one hydroxide source (OH − ), at least one structure-directing-agent (R), at least one seed source (Seed), and water (H 2 O) to form a mixture having the following mole composition (expressed in term of oxide): 
       YO 2 :(n)X 2 O 3 :(x)OH − :(y)R:(z)H 2 O+(m)Seed 
     wherein the m is in the range of from about 10 wtppm to about 2 wt. % (based on total weight of the synthesis mixture), the n is in the range of from about 0.005 to 0.05, the x is in the range of from about 0.01 to about 0.3, the y is in the range of from about 0.03 to about 2; and the z is in the range of from about 3 to about 30; and (b) treating said mixture under crystallization conditions to form said crystalline molecular sieve substantially free of non-MFS material, wherein said crystallization conditions comprise a temperature in the range of from about 150° C. to about 250° C., and crystallization time less than 100 hr, the weight hourly throughput is at least 0.001 hr −1 .

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/773,035, filed Feb. 14, 2006, the disclosures of which areincorporated herein by reference in its entirety.

FIELD

This invention relates to a process for the preparation of molecularsieve of MFS framework type and to its use in catalytic conversion oforganic compounds.

BACKGROUND OF THE INVENTION

Molecular sieves of the MFS framework type, and in particular ZSM-57,are useful catalyst components for a variety of conversion processes,such as hydrocarbon cracking, dehydrogenation, oligomerization,isomerization, disproportionation, and alkylation as well as theformation of hydrocarbons from oxygen-containing compounds such asalcohols and ethers.

The composition, properties and preparation of ZSM-57 are disclosed inEuropean Patent No. 174,121, and U.S. Pat. Nos. 4,873,067 and 4,973,781,the entire disclosures of these documents being incorporated byreference herein. ZSM-57 is a zeolite with a typical molar ratio ofYO₂:X₂O₃ of at least 4, wherein Y represents silicon and/or germaniumand X represents aluminum, and/or boron, and/or chromium, and/or iron,and/or gallium. Preferably, there are from greater than 8 to about 200moles of YO₂ per mole of X₂O₃. Preferably, YO₂ is silica and X₂O₃ isalumina.

ZSM-57 may be prepared as described in European Patent No. 174,121 froma synthesis mixture containing sources of alkali metal ions, an oxide ofsilicon, an oxide of aluminum, water and an organic directing agentwhich is a salt of N,N,N,N′,N′,N′-hexaethylpentane diammonium (HEPD,also known as hexaethyl-Diquat-5), and maintaining said mixture undercrystallization conditions until the required zeolite is formed. Thesynthesis mixture has a composition within the following ranges:SiO₂:Al₂O₃ of 20 to 200:1, preferably 40 to 100:1; H₂O:SiO₂ of 10 to200:1, preferably of 20 to 50:1; OH⁻:SiO₂ of 0 to 3:1, preferably 0.1 to0.5:1; Z:SiO₂ of 0 to 3:1, preferably of 0.1 to 2:1, where Z is analkali metal cation; R:SiO₂ of 0.01 to 2:1, preferably of 0.1:1, where Ris HEPD, preferably its dibromide salt. Crystallization of zeoliteZSM-57 may be carried out under either static or stirred conditions. Auseful range of temperatures for crystallization is from 80° C. to 350°C. for a time of 12 hours to 200 days. Thereafter, the crystals areseparated from the liquid and recovered. The synthesis of the zeolitecrystals is said to be facilitated by the presence of at least 0.01 wtpercent, preferably 0.10 wt %, and still more preferably 1 wt %, seedcrystals (based on total weight) of crystalline product.

U.S. Patent Application No. 20050013774 A1 discloses a process for themanufacture of a crystalline molecular sieve of the MFS framework type,which comprises hydrothermal treatment of a synthesis mixture containingsources of alkali metal ions, of aluminum, and of silicon, water, anN,N,N,N′,N′,N′-hexaethylpentane diammonium salt (HEPD), hereinafter R₁,and R₂, an amine of formula NR¹R²R³ or a quaternary ammonium compound offormula R¹R²R³R⁴NX, wherein R¹, R², R³, or R⁴, which may be identical ordifferent, each independently represent a hydrogen atom, a linear alkylgroup having from 1 to 8 carbon atoms, a branched alkyl group havingfrom 3 to 8 carbon atoms, or a cycloalkyl group having 5 or 6 carbonatoms, at least one of R¹, R², R³, and if present R⁴, being other thanhydrogen, and X represents an anion.

U.S. Pat. No. 4,873,067 further illustrates the preparation of boron,chromium, iron and/or gallium-containing zeolite ZSM-57 by a methodcomprising preparing a mixture containing sources of alkali metal ions,an oxide of silicon, an oxide of aluminum, a source of boron, and/orchromium, and/or iron and/or gallium, water and HEPD, and maintainingsaid mixture under crystallization conditions until the required zeoliteis formed.

Colloidal seeds have proved effective in controlling the particle sizeof the product, avoiding the need for an organic directing agent,accelerating synthesis, and improving the proportion of product that isof the intended framework type.

European Patent No. 1105348 provides a colloidal suspension of a LEVframework type crystalline molecular sieve and a method for preparing acolloidal suspension of LEV by synthesizing a LEV framework typecrystalline molecular sieve by treatment of an appropriate synthesismixture, separating the product from the synthesis mixture, washing theproduct, and recovering the resulting wash liquid.

The ZSM-57 material that is commercially available, however, isexpensive and time consuming for manufacturing. There is therefore aneed for an improved high throughput process for manufacturing theZSM-57 material. We have now found that the throughput of the processfor preparing the crystalline molecular sieves of the MFS framework typeis improved by lowering the alkali and the water content of thesynthesis mixture and/or by increasing the crystallization temperature.

SUMMARY OF THE INVENTION

In one embodiment, this invention relates to a method of making acrystalline molecular sieve of MFS framework type, the method comprisingthe steps of:

-   (a) providing a mixture comprising at least one source of ions of    tetravalent element (Y), at least one source of ions of trivalent    element (X), at least one hydroxide source (OH⁻), at least one    structure-directing-agent (R), at least one seed source (Seed), and    water (H₂O), said mixture having the following mole composition    (expressed in term of oxide):

YO₂:(n)X₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed

-   -   wherein m is in the range of from about 10 wtppm to about 2 wt.        %, preferably from about 10 to 2000 wtppm, and more preferably        from about 1000 to 2000 wtppm (based on total weight of the        synthesis mixture); n is in the range of from about 0.005 to        0.05, preferably from about 0.01 to 0.05; x is in the range of        from about 0.01 to about 0.3, preferably from about 0.01 to 0.2;        y is in the range of from about 0.03 to about 2, preferably from        about 0.03 to 0.2, more preferably from about 0.035 to 0.2, even        more preferably from about 0.04 to about 0.2; and z is in the        range of from about 3 to about 30, preferably from about 3 to        15, more preferably from about 3 to 10, optionally from about 8        to 10; and

-   (b) treating the mixture under crystallization conditions to form    the crystalline molecular sieve of MFS framework type,    wherein the structure-directing-agent R containing    N,N,N,N′,N′,N′-hexaethylpentane diammonium salt (R₁), the    crystallization conditions comprise a temperature in the range of    from about 150° C. to about 250° C., and crystallization time less    than 100 hr, and wherein the weight hourly throughput is at least    0.001 hr⁻¹.

In another embodiment, this invention relates to a process ofmanufacturing crystalline molecular sieve of MFS framework type, themethod comprising the steps of:

-   (a) providing a mixture comprising at least one silicon source    (SiO₂), at least one aluminum source (Al₂O₃), at least one hydroxide    source (OH⁻), at least one structure-directing-agent (R), LEV seeds,    and water (H₂O), said mixture having the following mole composition:

SiO₂:(n)Al₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed

-   -   wherein m is in the range of from about 10 wtppm to about 2 wt.        %, preferably from about 10 to 2000 wtppm, and more preferably        from about 1000 to 2000 wtppm (based on total weight of the        synthesis mixture); n is in the range of from about 0.005 to        0.05, preferably from about 0.01 to 0.05; x is in the range of        from about 0.01 to about 0.3, preferably from about 0.01 to 0.2;        y is in the range of from about 0.03 to about 2, preferably from        about 0.03 to 0.2, more preferably from about 0.035 to 0.2, even        more preferably from about 0.04 to about 0.2; and z is in the        range of from about 3 to about 30, preferably from about 3 to        15, more preferably from about 3 to 10, optionally from about 8        to 10;

-   (b) treating the mixture under crystallization conditions to form a    product containing crystalline molecular sieve of MFS framework    type; and

-   (c) recovering the crystalline molecular sieve of MFS framework type    from the product,    wherein the structure-directing-agent R comprises    N,N,N,N′,N′,N′-hexaethylpentane diammonium salt (R₁), the    crystallization conditions comprise a temperature in the range of    from about 150° C. to about 250° C., and crystallization time less    than 100 hr, and wherein the weight hourly throughput is at least    0.001 hr⁻¹.

In yet another embodiment, this invention relates to a crystallinemolecular sieve of MFS framework type manufactured by the processcomprising the steps of:

-   (a) providing a mixture comprising at least one silicon source    (SiO₂), at least one aluminum source (Al₂O₃), at least one hydroxide    source (OH⁻), at least one structure-directing-agent (R), LEV seeds,    and water (H₂O), said mixture having the following mole composition:

SiO₂:(n)Al₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed

-   -   wherein m is in the range of from about 10 wtppm to about 2 wt.        %, preferably from about 10 to 2000 wtppm, and more preferably        from about 1000 to 2000 wtppm (based on total weight of the        synthesis mixture); n is in the range of from about 0.005 to        0.05, preferably from about 0.01 to 0.05; x is in the range of        from about 0.01 to about 0.3, preferably from about 0.01 to 0.2;        y is in the range of from about 0.03 to about 2, preferably from        about 0.03 to 0.2, more preferably from about 0.035 to 0.2, even        more preferably from about 0.04 to about 0.2; and z is in the        range of from about 3 to about 30, preferably from about 3 to        15, more preferably from about 3 to 10, optionally from about 8        to 10;

-   (b) treating the mixture under crystallization conditions to form    the a product containing crystalline molecular sieve of MFS    framework type; and

-   (c) recovering the crystalline molecular sieve of MFS framework type    from the product,    wherein the structure-directing-agent R comprises    N,N,N,N′,N′,N′-hexaethylpentane diammonium salt (R₁), the    crystallization conditions comprise a temperature in the range of    from about 150° C. to about 250° C., and crystallization time less    than 100 hr, and wherein the weight hourly throughput is at least    0.001 hr⁻¹.

In an embodiment, this invention relates to a process for hydrocarbonconversion comprising the step of contacting the hydrocarbon with acrystalline molecular sieve of MFS framework type manufactured by themethod and/or process disclosed in the preceding paragraphs.

These and other facets of the present invention shall become apparentfrom the following detailed description, figures, and appended claims.

DESCRIPTION OF THE FIGURE

FIG. 1 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of the Reference Example.

FIG. 2 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of Example 1.

FIG. 3 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of Example 2.

FIG. 4 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of Example 3.

FIG. 5 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of Example 4.

FIG. 6 is the Scan Electronic Microscopy of the dried as-synthesizedsolid product of Example 5.

FIG. 7 is a plot of the reaction temperature versus the catalyst lifefor the ZSM-57 product of Examples 1, 2, 3, 4, 5, and Reference Exampleas tested in Example 6.

FIG. 8 is a plot of the C₈ selectivity versus the conversion of butenesfor the ZSM-57 product of Examples 1, 2, 3, 4, 5, and reference exampleas tested in Example 6.

DETAILED DESCRIPTION OF THE INVENTION

All patents, patent applications, test procedures, priority documents,articles, publications, manuals, and other documents cited herein arefully incorporated by reference to the extent such disclosure is notinconsistent with the present invention and for all jurisdictions inwhich such incorporation is permitted.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.

As used in this specification, the term “framework type” is used in thesense described in the “Atlas of Zeolite Framework Types,” eds. Ch.Baerlocher, W. H. Meier, and D. H. Olson, Elsevier, Fifth Edition, 2001,which is hereby incorporated by reference.

Synthetic zeolites are often prepared from aqueous synthesis mixturescomprising sources of appropriate oxides. Organic directing agents mayalso be included in the synthesis mixture for the purpose of influencingthe production of a zeolite having the desired structure. The use ofsuch directing agents is discussed in an article by Lok et al. entitled“The Role of Organic Molecules in Molecular Sieve Synthesis” appearingin Zeolites, Vol. 3, October, 1983, pp. 282-291.

The invention more especially provides a high throughput process for themanufacture of a crystalline molecular sieve of the MFS framework typewhich comprises subjecting to hydrothermal treatment a synthesis mixturehaving a composition within the molar ranges of:

 20 to 200 YO₂:X₂O₃  3 to 30 H₂O:YO₂ 0.01 to 0.3 OH⁻:YO₂ 0.01 to 0.3M⁺:YO₂ 0.03 to 2   R:YO₂wherein M⁺ represents an alkali metal ion, R represents directing agent,e.g., R₁ (HEPD) or R₁ with additional directing agent R₂. When both R₁and R₂ are present in the synthesis mixture, the synthesis mixturepreferably has a composition within the molar ranges of:

 20 to 200 YO₂:X₂O₃  3 to 30 H₂O:YO₂ 0.01 to 0.3 OH⁻:YO₂ 0.01 to 0.3M⁺:YO₂ 0.015 to 2   R₁:YO₂ 0.015 to 2   R₂:YO₂ 0.03 to 2   (R₁ + R₂):YO₂

Preferred molar ranges are:

 40 to 100 YO₂:X₂O₃  3 to 15 H₂O:YO₂ 0.05 to 0.2 OH⁻:YO₂ 0.05 to 0.2M⁺:YO₂ 0.015 to 0.3  R₁:YO₂ 0.015 to 0.3  R₂:YO₂

It will be understood by a person skilled in the art that the synthesismixture having a composition within the molar ranges as discussed abovemeans that the synthesis mixture is the product of mixing, adding,reacting, or by any means of providing such a mixture, wherein suchproduct has a composition within the molar ranges as discussed above.The product of mixing, adding, reacting, or by any means of providingsuch a mixture may or may not contain individual ingredients when theproduct was prepared. The product of mixing, adding, reacting, or by anymeans of providing such a mixture, may even contain reaction product ofindividual ingredients when the product was prepared by mixing, adding,reacting, or by any means of providing such a mixture.

It will be understood by a person skilled in the art that thecrystalline molecular sieve manufactured by the process or method ofthis invention may contain impurities, such as amorphous materials; unitcells having non-MFS framework topologies (e.g., MFI, MTW); and/or otherimpurities (e.g., heavy metals and/or organic hydrocarbons). Thecrystalline molecular sieve manufactured by the process or method ofthis invention is preferably substantially free of non-MFS material. Theterm “substantially free of non-MFS material” used herein means thecrystalline molecular sieve contains minor proportion (less than 50 wt.%), preferably less than 20 wt. %, more preferably less than 10 wt. %,even more preferably less than 5 wt. %, and most preferably less than 1wt. %, of such non-MFS materials based on the combination weight ofnon-MFS materials and the molecular sieve(s) of MFS framework type. Theterm “non-MFS material” used herein means any material does not containcrystalline molecular sieve of MFS framework type. Examples of suchnon-MFS material are amorphous material, ZSM-5 (MFI framework type),mordenite (MOR framework type), Y and X zeolites (FAU framework type),and MCM-22 (MWW framework type). The non-MFS material may co-crystallizewith the MFS material or mix with the MFS material.

The sources of the various elements required in the final product may beany of those in commercial use or described in the literature, as maythe method of preparation of the synthesis mixture.

In the present synthesis method, the source of ions of tetravalentelement Y preferably comprises solid YO2, preferably about 30 wt. %solid YO2 in order to obtain the crystal product of this invention.Examples of tetravalent element are silicon, germanium, and tin. WhenYO2 is silica, the use of a silica source containing preferably about 30wt. % solid silica, e.g., silica sold by Degussa under the trade namesAerosil or Ultrasil (a precipitated, spray dried silica containing about90 wt. % silica), an aqueous colloidal suspension of silica, for exampleone sold by Grace Davison under the trade name Ludox, or HiSil (aprecipitated hydrated SiO2 containing about 87 wt. % silica, about 6 wt.% free H2O and about 4.5 wt. % bound H2O of hydration and having aparticle size of about 0.02 micro) favors crystal formation from theabove mixture. Preferably, therefore, the YO2, e.g., silica, sourcecontains about 30 wt. % solid YO2, e.g., silica, and more preferablyabout 40 wt. % solid YO2, e.g., silica. The source of silicon may alsobe a silicate, e.g., an alkali metal silicate, or a tetraalkylorthosilicate.

The source of ions of trivalent element X, e.g., aluminum, boron,gallium, and iron, is preferably aluminum sulphate or hydrated alumina.Other aluminum sources include, for example, other water-solublealuminum salts, sodium aluminate, or an alkoxide, e.g., aluminumisopropoxide, or aluminum metal, e.g., in the form of chips.

The alkali metal is advantageously potassium or sodium, the sodiumsource advantageously being sodium hydroxide or sodium aluminate.

Directing Agent

The directing agent used in this invention comprises anN,N,N,N′,N′,N′-hexaethylpentane diammonium salt (HEPD), hereinafter R₁,optionally with one or another directing agent, R₂, were R₂ comprises anamine of formula NR¹R²R³ or a quaternary ammonium compound of formulaR¹R²R³R⁴NA, wherein R¹, R², R³, or R⁴, which may be identical ordifferent, each independently represent a hydrogen atom, a linear alkylgroup having from 1 to 8 carbon atoms, a branched alkyl group havingfrom 3 to 8 carbon atoms, or a cycloalkyl group having 5 or 6 carbonatoms, at least one of R¹, R², R³, and if present R⁴, being other thanhydrogen, and A represents an anion. Mixtures of two or more compoundsR₁ may be used. Mixtures of two or more compounds R₂ may also be used.These may be mixtures of two or more amines, or of two or morequaternary compounds, or of one or more amines and one or morequaternary compounds.

As amine for use as a second organic molecule there may be mentioned,for example, mono, di- and tri-methylamine, mono-, di- andtriethylamine, mono-, di- and tri propylamines, mono-, di- andtrihexylamines, mono-, di- and triheptylamines, mono-, di- andtrioctylamines, cyclopentylamine and cyclohexylamine. Advantageously,the amine is a triamine, i.e., none of R¹, R², and R³ representshydrogen. Preferably, the amine of formula NR¹R²R³ is selected fromtrimethylamine, triethylamine and a tripropylamine; most preferably itis triethylamine. Advantageously, the quaternary ammonium compoundcorresponds to one of the above amines, and is preferably atetralkylammonium compound, preferably a tetramethyl-, tetraethyl-, ortetrapropyl-ammonium compound, a tetra ethylammonium compound being mostpreferred. As examples of the anion there may be mentioned halide,especially chloride or bromide, and hydroxide. Mixtures of thesecompounds may be used, as indicated above.

LEV Seed

The synthesis may be aided by seeds from a previous synthesis, the seedsbeing advantageously colloidal or near-colloidal. Seeds of a differentframework type, especially LEV, may be used. The preparation ofcolloidal LEV seeds is described in International application WO00/06494. Seeds are advantageously present in a proportion of from0.0001 wt. % (10 weight part per million or “wtppm”) to 2 wt. %,preferably 0.001 wt. % to 1 wt. %, more preferably 0.01 wt. % to 0.5 wt.%, by weight, based on the total weight of synthesis mixture. Forcertain synthesis mixtures, a pure MFS framework type material is morereadily obtained with seeding.

As used herein, the term “colloidal”, when used of a suspension, refersto one containing discrete finely divided particles dispersed in acontinuous liquid phase and preferably refers to a suspension that isstable, in the sense that no visible separation occurs or sedimentforms, in a period sufficient for the use intended, advantageously forat least 10, more advantageously at least 20, preferably at least 100,and more preferably at least 500, hours at ambient temperature (23° C.).The maximum size of the particles for the suspension to remain stable(peptized) will depend to some extent on their shape, and on the natureand pH of the continuous medium, as well as on the period during whichthe suspension must remain usable. In general, the maximum dimensionwill be 500, advantageously 400, preferably 300, more preferably 200,and most preferably 100, nm. The particles may be spherical, or of othershapes. Where particles are other than spherical, the dimension referredto is their smallest dimension.

As indicated above, the colloidal seeds have utility in the manufactureof a variety of crystalline molecular sieves by incorporating the seedsas a component of a synthesis mixture. They are advantageouslyincorporated in the synthesis mixture in the form of a suspension,advantageously in an aqueous medium, preferably water, or another liquidcomponent of the synthesis mixture. Less preferably they may be added indry, but not calcined, form. It is believed that calcinationsignificantly reduces the activity of small crystallites to act asseeds; similarly any other treatment that reduces the seeding activityof materials should be avoided.

Crystallization Conditions

In general, the treatment of the synthesis mixture to yield the desiredcrystalline molecular sieve, usually termed hydrothermal treatment isconveniently carried out under autogenous pressure, for example in anautoclave, which may, if desired, be PTFE-lined. The treatment may, forexample, be carried out at a temperature within the range of from 50,advantageously from 90, especially 120, preferably 150, to 250° C. Thetreatment may, for example, be carried out for a period within the rangeof from 1 to less than 100 hours, preferably up to 72 hours. Theprocedure may include an aging period, either at room temperature or,preferably, at a moderately elevated temperature, before thehydrothermal treatment at more elevated temperature. The latter mayinclude a period of gradual or stepwise variation in temperature.

The hydrothermal treatment may be carried out under the usual molecularsieve synthesis conditions. Advantageously used are temperatures withinthe range of from 100° C. to 250° C., preferably from 150° C. to 200°C., and more preferably from 160° C. to 180° C. Temperature may beincreased, gradually or stepwise, during treatment. Advantageously, atime within the range of from 1 to less than 100 hours, preferably from10 to less than 72 hours, and conveniently from 20 to 48 hours, isemployed, lower temperatures corresponding to longer times.

For certain applications, the treatment is carried out with any type ofagitation, e.g., stirring or rotating the vessel about a horizontal axis(tumbling). For other applications, static hydrothermal treatment ispreferred. If desired, the synthesis mixture may be stirred or tumbledduring an initial part of the heating stage, for example, from roomtemperature to an elevated, e.g., the final treatment, temperature, andbe static for the remainder. Agitation generally produces a product witha smaller particle size and a narrower particle size distribution thanstatic hydrothermal treatment.

It has been found that for certain synthesis mixture compositions, apure MFS framework type material is more readily obtained when synthesisis carried out with agitation. For a composition that gives purematerial whether synthesis is carried out with or without agitation,crystal size is normally greater if the synthesis is carried out withoutagitation.

The procedure may include an aging period, either at room temperature orat a moderately elevated temperature, lower than that used for thehydrothermal treatment.

The term “throughput” used herein means the amount of crystallinemolecular sieve produced per unit time (hour) and per unit volume of thesynthesis gel (volume hourly throughput) or per unit weight of thesynthesis gel (weight hourly throughput). The higher the throughput, themore crystalline molecular sieve produced per unit volume of the reactorand per unit amount of time. Therefore, for the same amount of thecrystalline molecular sieve synthesized, the higher the throughput,generally the smaller the reactor (autoclave) needed or the shorter thetime required for each synthesis. The volume hourly throughput for asynthesis may be calculated by dividing the volume of the molecularsieve produced (after drying at 120° C. for 24 hours) with the volume ofthe synthesis gel and the total time required for the crystallization asfollows:

$\begin{matrix}{{volume}\mspace{14mu} {hourly}} \\{throughput}\end{matrix} = \frac{\begin{matrix}{{volume}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {molecular}\mspace{14mu} {sieve}\mspace{14mu} {produced}} \\\left( {{dried}\mspace{14mu} {at}\mspace{14mu} 120{^\circ}\mspace{11mu} {C.\mspace{14mu} {for}}\mspace{14mu} 24\mspace{14mu} {hours}} \right)\end{matrix}}{\begin{matrix}{\left( {{volume}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {synthesis}\mspace{14mu} {gel}} \right) \times} \\\left( {{time}\mspace{14mu} {required}\mspace{14mu} {for}\mspace{14mu} {the}\mspace{14mu} {crystallization}} \right)\end{matrix}}$

The weight hourly throughput for a synthesis may be calculated bydividing the weight of the molecular sieve produced (after drying at120° C. for 24 hours) with the weight of the synthesis gel and the totaltime required for the crystallization as follows:

$\begin{matrix}{{weight}\mspace{14mu} {hourly}} \\{throughput}\end{matrix} = \frac{\begin{matrix}{{weight}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {molecular}\mspace{14mu} {sieve}\mspace{14mu} {produced}} \\\left( {{dried}\mspace{14mu} {at}\mspace{14mu} 120{^\circ}\mspace{11mu} {C.\mspace{14mu} {for}}\mspace{14mu} 24\mspace{14mu} {hours}} \right)\end{matrix}}{\begin{matrix}{\left( {{weight}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {synthesis}\mspace{14mu} {gel}} \right) \times} \\\left( {{time}\mspace{14mu} {required}\mspace{14mu} {for}\mspace{14mu} {the}\mspace{14mu} {crystallization}} \right)\end{matrix}}$

In one aspect of this invention, the weight hourly throughput for thisinvention is at least 0.001 hr⁻¹, preferably at least 0.002 hr⁻¹, morepreferably at least 0.004 hr⁻¹, and most preferably at least 0.008 hr⁻¹.

The weight hourly throughput of a synthesis may be adjusted by changingsolid-content, amount of seed used in the synthesis gel, crystallizationtemperature, time for crystallization, and/or any combination thereof.The weight hourly throughput and these parameters mentioned above areinterrelated. Changing one parameter may affect other parameters. Forexample, by increasing weight hourly throughput of a synthesis undercertain crystallization conditions, e.g., crystallization temperatureand time, the solid-content and/or the amount of seed crystal may haveto increase.

One factor affecting the synthesis of a crystalline molecular sieve isthe solid-content in a synthesis mixture. The term “solid-content” usedherein means the weight percentage of both trivalent and tetravalentelements (calculated as oxides) in the synthesis mixture. It can bemeasured by dividing the weight of both trivalent and tetravalent oxidesin the synthesis mixture by the total weight of the synthesis mixture asfollows:

${{solid}\text{-}{content}} = \frac{\begin{matrix}{{the}\mspace{14mu} {weight}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {oxides}\mspace{14mu} {in}} \\{{the}\mspace{14mu} {synthesis}\mspace{14mu} {mixture}}\end{matrix}}{{total}\mspace{14mu} {weight}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {synthesis}\mspace{14mu} {mixture}}$

The term “high solid” used herein means that the solid-content of asynthesis mixture is at least 12 wt. %, preferably at least 15 wt. %,more preferably at least 18 wt. %, yet more preferably at least 20 wt.%, and most preferably at least 30 wt. %.

Another factor affecting the synthesis of a crystalline molecular sieveis the amount of hydroxide present (e.g., alkali content), which isrepresented by the molar ratio of the alkali oxides over silica. Webelieve that the higher the solid-content, the lower the hydroxideneeded in the synthesis gel to achieve high crystallinity of the ZSM-57product.

We surprisingly found the combination of high solid-content and lowalkali content greatly improves the throughput of the ZSM-57 synthesis.As demonstrated in the examples following, the weight hourly throughputincreases from about 200% to about 600% under similar content of seedsand crystallization temperature.

Another factor affecting the synthesis of a crystalline molecular sieveis the temperature. High temperature, e.g., greater than 200° C., maydamage the directing agent in the synthesis mixture. To performcrystallization at high temperature, more directing agent may be neededsince some of the directing agent might be damaged by the causticreactant(s) in the synthesis mixture at the high temperature. Generally,the higher the temperature, the faster the crystallization rate.However, higher temperature may damage the expensive directing agent,which in fact slows the rate of the crystallization process. The term“high temperature” as used herein means the crystallization temperatureranges from 160 to 250° C. for the synthesis of a molecular sieve havinga structure of MFS.

The synthesis mixture may contain seed crystal. It is well known thatseeding a molecular sieve synthesis mixture frequently has beneficialeffects, for example in controlling the particle size of the product,avoiding the need for an organic directing agent, acceleratingsynthesis, and improving the proportion of product that is of theintended framework type. In one embodiment of this invention, synthesisof the crystalline molecular sieve is facilitated by the presence of atleast 0.001 wt. % seed crystals (based on total weight of the synthesismixture).

We surprisingly found the additional seeds and/or higher crystallizationtemperature in combination with high solid-content and low alkalicontent further improves the throughput of the ZSM-57 synthesis. Asdemonstrated in the examples follows, the weight hourly throughputfurther increases from about 600% to about 1200% under similarsolid-content and alkali content conditions.

Hydrocarbon Conversion Using ZSM-57 Material

The direct product of the synthesis described above may be calcined,cation-exchanged, and otherwise treated as is known in the art. Alkalimetal cations in the as-prepared or calcined form may be removed, forexample by treatment with concentrated acids, e.g., HCl, or with afugitive base, e.g., an ammonium compound, to provide the material inits hydrogen form.

The products of the invention, if required after cation exchange and/orcalcining, have utility as catalyst precursors, catalysts, andseparation and absorption media. They are especially useful in numerousorganic, e.g., hydrocarbon, compound conversions, separations andabsorptions. They may be used alone, or in admixture with othermolecular sieves, in particulate form, supported or unsupported, or inthe form of a supported layer. Hydrocarbon conversions include, forexample, cracking, reforming, hydrofining, aromatization,oligomerization (e.g., di- and trimerization, especially of olefinshaving 3 to 6 carbon atoms, more especially butene trimerization),isomerization, dewaxing, and hydrocracking (e.g., naphtha to lightolefins, higher to lower molecular weight hydrocarbons, alkylation,transalkylation, disproportionation or isomerization of aromatics).Other conversions include the reaction of alcohols with olefins and theconversion of oxygenates to hydrocarbons.

EXAMPLES

The following numbered examples, in which all parts percentages are byweight unless otherwise indicated, illustrate the invention. Percentageyields are based on the total weight of synthesis mixture.

The N,N,N,N′,N′,N′-hexaethylpentane diammonium dibromide (HEPD) wasprepared according to the following procedure:

1 mole of 1,5-dibromopentane and 2 moles of triethylamine were dissolvedin ethanol and refluxed overnight. The resulting solution wasconcentrated and finally evaporated to dryness under vacuum at 35° C.The white product was recrystallized from ether and identified as HEPD(hereinafter R₁).

The LEV seeds sample was prepared according to the disclosure inInternational application WO 00/06494.

The SEM images were obtained on a JEOL JSM-6340F Field Emission ScanningElectron Microscope (SEM), using a magnification at a voltage of 2 keV.

The XRD diffraction patterns were recorded on a Stoe Stadi PDiffractometer in transmission mode, using Cu K-α radiation.

Reference Example

A synthesis mixture was prepared containing the following ingredients: asodium aluminate solution (12.34 wt. % NaOH and 3.06 wt. % Al(OH)₃ inwater, Alcoa Corporation, Pittsburgh, Pa., USA), a 25 wt. % solution ofN,N,N,N′,N′,N′-hexaethylpentane di-ammonium dibromide, a 50 wt. %solution of tetraethyl ammonium bromide in water (hereinafter R₂),silica (Ultrasil VN 35P, 92.4 wt. % of SiO₂) and a 1 wt. % NaOH solutionin water. To 21.2 parts of distilled water were added 0.49 parts of theNaOH solution. To this solution were added 0.12 parts of the sodiumaluminate solution while stirring. This solution was stirred for 5minutes before 0.45 parts of solution R₁ were added. After 5 minutes ofadditional stirring, 0.22 parts of solution R₂ were added, followed by0.2 parts of a seeding slurry containing 5 wt. % of LEV seeds. After 5minutes of mixing, 2.54 parts of the Ultrasil were added. The synthesismixture, having the following molar composition:

0.148Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO₂:28H₂O+400 wtppm of LEV seeds

was stirred an additional 10 minutes before transferring to an autoclaveand heated to 160° C. with a ramp rate of 25° C./hr, while stirring at100 rotation per minute (“rpm”). The crystallization was continued for120 hrs at 160° C.

After crystallization a solid product was recovered from thecrystallization mixture, washed, and dried at 120° C. The yield of thecrystallization was 9.3 wt. %. The SEM of the dried solid product showedplate morphology (FIG. 1). XRD analysis of the dried solid productshowed it to be ZSM-57, a zeolite of the MFS framework type. Anelemental analysis of the dried solid product showed a Si/Al₂ ratio of43.6. The solid-content of the synthesis mixture was about 10.5 wt. %.The weight hourly throughput was 0.0008 hr⁻¹.

Example 1

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.13Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO₂:18H₂O+400 wtppm of LEV seeds

This mixture was transferred to an autoclave and heated to 160° C. witha ramp rate of 25° C./hr, while stirring at 100 rpm. The crystallizationwas continued for 72 hrs at 160° C. After crystallization a solidproduct was recovered from the crystallization mixture, washed, anddried at 120° C. The SEM of the dried solid product showed platemorphology (FIG. 2). XRD analysis of the dried solid product showed itto be ZSM-57. The yield of the crystallization was 12.1 wt. %. Elementalanalysis of the dried solid product showed a Si/Al₂ ratio of 42.6. Thesolid-content of the synthesis mixture was about 15.1 wt. %. The weighthourly throughput was 0.0017 hr⁻¹. The weight hourly throughputincreased by about 220% in comparison with the reference example.

Comparative Example 2A

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.12Na₂O:0.018Al₂O₃ :0.0246R₁:0.0246R₂:SiO₂:13H₂O+400 wtppm of LEV seeds

This mixture was transferred to an autoclave and heated to 160° C. witha ramp rate of 25° C./hr, while stirring at 100 rpm. The crystallizationwas continued for 72 hrs at 160° C. After crystallization a solidproduct was recovered from the crystallization mixture, washed, anddried at 120° C. XRD analysis of the dried material showed it to be someZSM-57 contaminated with mordenite. The yield of the crystallizationincluding both ZSM-57 and mordenite was 17 wt. %. The solid-content ofthe synthesis mixture was about 19.4 wt. %. The weight hourly throughputwas 0.0024 hr⁻¹. The weight hourly throughput increased by about 300% incomparison with the reference example.

Example 2

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.11Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO₂:13H₂O+400 wtppm of LEV seeds

This mixture was transferred to an autoclave and heated to 160° C. witha ramp rate of 25° C./hr, while stirring at 100 rpm. The crystallizationwas continued for 72 hrs at 160° C. After crystallization a solidproduct was recovered from the crystallization mixture, washed, anddried at 120° C. The SEM of the dried solid product showed platemorphology (FIG. 3). XRD analysis of the dried solid product showed itto be ZSM-57. The yield of the crystallization was 17.4 wt. %. Elementalanalysis of the dried solid product showed a Si/Al₂ ratio of 45.9. Thesolid-content of the synthesis mixture was about 19.4 wt. %. The weighthourly throughput was 0.0024 hr⁻¹. The weight hourly throughputincreased by about 310% in comparison with the reference example.

Example 3

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.11Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO₂:10H₂O+1500 wtppm of LEV seeds

This mixture was transferred to an autoclave and heated to 160° C. witha ramp rate of 25° C./hr, while stirring at 100 rpm. The crystallizationwas continued for 48 hrs at 160° C. After crystallization a solidproduct was recovered from the crystallization mixture, washed, anddried at 120° C. XRD analysis of the dried solid product showed it to beZSM-57. The yield of the crystallization was 23.4 wt. %. The SEM of thedried solid product showed plate morphology (FIG. 4). Elemental analysisof the dried solid product showed a Si/Al₂ ratio of 44.4. Thesolid-content of the synthesis mixture was about 24.9 wt. %. The weighthourly throughput was 0.0045 hr⁻¹. The weight hourly throughputincreased by about 580% in comparison with the reference example.

Example 4

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.11Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO2:10H₂O+2000 wtppm of LEV seeds

This mixture was heated to 170° C. with a ramp rate of 25° C./hr, whilestirring at 100 rpm. The reaction was continued for 36 hrs at 170° C.After crystallization the solid product was recovered from the reactionmixture, washed, and dried at 120° C. XRD analysis of the materialshowed it to be ZSM-57. The yield of the reaction was 18.7 wt. %.Elemental analysis of the dried solid product showed a Si/Al₂ ratio of43.3. The solid-content of the synthesis mixture was about 23.4 wt. %.The weight hourly throughput was 0.0052 hr⁻¹. The SEM of the dried solidproduct showed plate morphology (FIG. 5). The weight hourly throughputincreased by about 670% in comparison with the reference example.

Example 5

A synthesis mixture was prepared by the procedure and raw materials usedas the reference example, but with the following molar composition:

0.11Na₂O:0.018Al₂O₃:0.0246R₁:0.0246R₂:SiO₂:10H₂O+2000 wtppm of LEV seeds

This mixture was heated to 180° C. with a ramp rate of 25° C./hr, whilestirring at 100 rpm. The reaction was continued for 24 hrs at 180° C.After crystallization the solid product was recovered from the reactionmixture, washed, and dried at 120° C. XRD analysis of the materialshowed it to be ZSM-57. The yield of the reaction was 20.8 wt %.Elemental analysis of the dried solid product showed a Si/Al₂ ratio of44.7. The solid-content of the synthesis mixture was about 23.4 wt. %.The weight hourly throughput was 0.0087 hr⁻¹. The SEM of the dried solidproduct showed plate morphology (FIG. 6). The weight hourly throughputincreased by about 1100% in comparison with the reference example.

Example 6

The materials of examples 1, 2, 3, 4, 5 and the reference example wereion-exchanged with NH₄Cl according to the following procedure. Two grammaterial of any one of the examples 1, 2, 3, 4, 5 and the referenceexample was brought in 200 ml 0.5 N NH₄Cl. The mixture was heated toabout 100° C. and hold under reflux overnight. After cooling, themixture was washed on a filter with distilled water until the wash waterwas substantially chloride free. The catalyst was dried at 120° C.overnight followed by calcination in air at 510° C. for 16 hours. Thepowders were pelletized, i.e., crushed and sieved to 300-600 microns.

A catalyst was made by diluting 0.25 g pellets with 29.75 g SiC (0.5mm). The catalyst was then loaded in a reactor for buteneoligomerization test. The testing conditions were: a feed rate of 25g/hr using a feed composed of 65 wt. % butene-1, 10 wt. % isobutane and25 wt. % n-butane; a temperature of 195° C., and a pressure of 101kPa-a. The heating was done electrically controlled by a thermocouple inthe heating jacket around the reactor. The reaction temperature wasmeasured via two thermocouples in the reactor. The conversion of thebutene in weight percentage (wt. %) was measured by a HP5890 GC equippedwith a HP-1 (30 meter) and a HP-Al/S (50 meter) column. The selectivityto eight-carbon hydrocarbons (C₈) was measured by dividing the weight ofthe C₈ product with the weight of the butene converted. The deactivationof the catalyst was measured at a given temperature. The catalyst lifewas measured by the total weight of the butene converted (beforeregeneration of the catalyst) per unit weight of the catalyst.

FIG. 7 showed the temperature of the reaction versus the catalyst lifefor all catalysts made from the materials of examples 1, 2, 3, 4, 5 andthe reference example. FIG. 8 showed the selectivity to the C₈ versusthe conversion of the butene for all catalysts made from the materialsof examples 1, 2, 3, 4, 5 and the reference example. The materials ofexamples 1, 2, 3, 4, 5 and the reference example showed similaractivity, selectivity, and catalyst life for the butene oligomerizationreaction.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present invention,including all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

1. A method of making a crystalline molecular sieve of MFS frameworktype, said method comprising the steps of: (a) providing a mixturecomprising at least one source of ions of tetravalent element (Y), atleast one source of ions of trivalent element (X), at least onehydroxide source (OH⁻), at least one structure-directing-agent (R), atleast one seed source (Seed), and water (H₂O), said mixture having thefollowing mole composition (expressed in term of oxide):YO₂:(n)X₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed wherein m is in the range of fromabout 10 wtppm to about 2 wt. % (based on total weight of the synthesismixture), n is in the range of from about 0.005 to 0.05, x is in therange of from about 0.01 to about 0.3, y is in the range of from about0.03 to about 2; and z is in the range of from about 3 to about 30; and(b) treating said mixture under crystallization conditions to form saidcrystalline molecular sieve of MFS framework type, wherein saidstructure-directing-agent R comprises N,N,N,N′,N′,N′-hexaethylpentanediammonium salt (R₁), said crystallization conditions comprise atemperature in the range of from about 150° C. to about 250° C., and acrystallization time less than 100 hr, and wherein the weight hourlythroughput is at least 0.001 hr⁻¹.
 2. The method recited in claim 1,wherein said tetravalent element is silicon.
 3. The method recited inclaim 1, wherein said trivalent element is aluminum.
 4. The methodrecited in claim 1, wherein said seed is seed crystals of LEV frameworktype.
 5. The method recited in claim 1, wherein said source of ions oftetravalent element is colloidal silica, said source of ions oftrivalent element is aluminum sulphate and/or aluminum hydroxide, saidhydroxide source is alkali metal hydroxide, and said seed source is LEVseeds.
 6. The method recited in claim 1, wherein saidstructure-directing-agent R further comprising R₂, being an amine offormula NR¹R²R³ or a quaternary ammonium compound of formula R¹R²R³R⁴NA,wherein R¹, R², R³, or R⁴, which may be identical or different, eachindependently represents a hydrogen atom, a linear alkyl group havingfrom 1 to 8 carbon atoms, a branched alkyl group having from 3 to 8carbon atoms, or a cycloalkyl group having 5 or 6 carbon atoms, at leastone of R¹, R², R³, and if present R⁴, being other than hydrogen, and Arepresents an anion, wherein the molar ratio of the sum of R₁ and R₂over YO₂ is in the range of from about 0.03 to about 2 and the molarratio of R₁ over YO₂ is in the range of from about 0.015 to about
 2. 7.The method recited in claim 6, wherein none of R¹, R², R³ and if presentR⁴, is hydrogen.
 8. The method recited in claim 6, wherein R₂ istrimethylamine, triethylamine or tripropylamine.
 9. The method recitedin claim 6, wherein R₂ is a tetraethylammonium halide or hydroxide. 10.The method recited in claim 9, wherein the halide is the bromide orchloride.
 11. The method recited in claim 1, wherein said crystallinemolecular sieve product formed in step (b) is substantially free ofnon-MFS framework type material.
 12. The method recited in claim 1,wherein said crystalline molecular sieve is ZSM-57.
 13. The methodrecited in claim 1, wherein the weight hourly throughput is at least0.002 hr⁻¹.
 14. The method recited in claim 1, wherein the weight hourlythroughput is at least 0.004 hr⁻¹.
 15. The method recited in claim 1,wherein the weight hourly throughput is at least 0.008 hr⁻¹.
 16. Themethod recited in claim 1, wherein said crystallization conditionscomprise a temperature in the range of from about 160° C. to about 200°C.
 17. The method recited in claim 16, wherein said crystallization timeless than 72 hr.
 18. The method recited in claim 1, wherein saidcrystallization conditions comprise a temperature in the range of fromabout 165° C. to about 180° C.
 19. The method recited in claim 18,wherein said crystallization time less than 48 hr.
 20. The methodrecited in claim 1, wherein said m is from 10 to 2000 wtppm.
 21. Themethod recited in claim 1, wherein said m is from 1000 to 2000 wtppm.22. The method recited in claim 1, wherein said x is from 0.01 to 0.2.23. The method recited in claim 1, wherein said z is from 3 to
 15. 24.The method recited in claim 1, wherein said z is from 8 to
 10. 25. Themethod recited in claim 1, wherein said y is from 0.035 to 0.2.
 26. Themethod recited in claim 1, wherein said y is from 0.04 to 0.2.
 27. Themethod recited in claim 1, wherein said mixture has solid content of atleast 15 wt. %.
 28. The method recited in claim 1, wherein said mixturehas solid content of at least 18 wt. %.
 29. The method recited in claim1, wherein said mixture has solid content of at least 20 wt. %.
 30. Aprocess of manufacturing crystalline molecular sieve of MFS frameworktype, said method comprising the steps of: (a) providing a mixturecomprising at least one source of ions of tetravalent element (Y), atleast one source of ions of trivalent element (X), at least onehydroxide source (OH⁻), at least one structure-directing-agent (R), atleast one seed source (Seed), and water (H₂O), said mixture having thefollowing mole composition (expressed in term of oxide):YO₂:(n)X₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed wherein m is in the range of fromabout 10 wtppm to about 2 wt. % (based on total weight of the synthesismixture), n is in the range of from about 0.005 to 0.05, x is in therange of from about 0.01 to about 0.3, y is in the range of from about0.03 to about 2; and z is in the range of from about 3 to about 30; and(b) treating said mixture under crystallization conditions to form saidcrystalline molecular sieve of MFS framework type, and (c) recoveringsaid crystalline molecular sieve of MFS framework type from saidproduct, wherein said structure-directing-agent containingN,N,N,N′,N′,N′-hexaethylpentane diammonium salt (R₁), saidcrystallization conditions comprise a temperature in the range of fromabout 150° C. to about 250° C., and crystallization time less than 100hr, and wherein the weight hourly throughput is at least 0.001 hr⁻¹. 31.The process recited in claim 30, wherein said z is from 3 to less than10.
 32. The process recited in claim 30, wherein saidstructure-directing-agent R further comprises R₂, being an amine offormula NR¹R²R³ or a quaternary ammonium compound of formula R¹R²R³R⁴NA,wherein R¹, R², R³, or R⁴, which may be identical or different, eachindependently represent a hydrogen atom, a linear alkyl group havingfrom 1 to 8 carbon atoms, a branched alkyl group having from 3 to 8carbon atoms, or a cycloalkyl group having 5 or 6 carbon atoms, at leastone of R¹, R², R³, and if present R⁴, being other than hydrogen, and Arepresents an anion, wherein the molar ratio of the sum of R₁ and R₂over YO₂ is in the range of from about 0.03 to about 2 and the molarratio of R₁ over YO₂ is in the range of from about 0.015 to about
 2. 33.The process recited in claim 32, wherein none of R¹, R², R³ and ifpresent R⁴, is hydrogen.
 34. The process recited in claim 32, wherein R₂is trimethylamine, triethylamine or tripropylamine.
 35. The processrecited in claim 32, wherein R₂ is a tetraethylammonium halide orhydroxide.
 36. The process recited in claim 35, wherein the halide isthe bromide or chloride.
 37. The process recited in claim 30, whereinthe weight hourly throughput is at least 0.002 hr⁻¹.
 38. The processrecited in claim 30, wherein the weight hourly throughput is at least0.004 hr⁻¹.
 39. The process recited in claim 30, wherein the weighthourly throughput is at least 0.008 hr⁻¹.
 40. The process recited inclaim 30, wherein said crystallization conditions comprise a temperaturein the range of from about 160° C. to about 200° C.
 41. The processrecited in claim 40, wherein said crystallization time less than 72 hr.42. The process recited in claim 30, wherein said crystallizationconditions comprise a temperature in the range of from about 165° C. toabout 180° C.
 43. The process recited in claim 42, wherein saidcrystallization time less than 48 hr.
 44. The process recited in claim30, wherein said crystalline molecular sieve product formed in step (b)is substantially free of non-MFS framework type material.
 45. Theprocess recited in claim 30, wherein said m is from 10 to 2000 wtppm.46. The process recited in claim 30, wherein said m is from 1000 to 2000wtppm.
 47. The process recited in claim 30, wherein said x is from 0.01to 0.2.
 48. The process recited in claim 30, wherein said z is from 3 to15.
 49. The process recited in claim 30, wherein said z is from 3 to 10.50. The process recited in claim 30, wherein said y is from 0.035 to0.2.
 51. The process recited in claim 30, wherein said y is from 0.04 to0.2.
 52. The process recited in claim 30, wherein said mixture has solidcontent of at least 15 wt. %.
 53. The process recited in claim 30,wherein said mixture has solid content of at least 18 wt. %.
 54. Acrystalline molecular sieve of MFS framework type manufactured by theprocess comprising the steps of: (a) providing a mixture comprising atleast one source of ions of tetravalent element (Y), at least one sourceof ions of trivalent element (X), at least one hydroxide source (OH⁻),at least one structure-directing-agent (R), at least one seed source(Seed), and water (H₂O), said mixture having the following molecomposition (expressed in term of oxide):YO₂:(n)X₂O₃:(x)OH⁻:(y)R:(z)H₂O+(m)Seed wherein m is in the range of fromabout 10 wtppm to about 2 wt. % (based on total weight of the synthesismixture), n is in the range of from about 0.005 to 0.05, x is in therange of from about 0.01 to about 0.3, y is in the range of from about0.03 to about 2; and z is in the range of from about 3 to about 30; and(b) treating said mixture under crystallization conditions to form saidcrystalline molecular sieve of MFS framework type, (c) recovering saidcrystalline molecular sieve of MFS framework type from said product,wherein said structure-directing-agent containingN,N,N,N′,N′,N′-hexaethylpentane diammonium salt (R₁), saidcrystallization conditions comprise a temperature in the range of fromabout 150° C. to about 250° C., and crystallization time less than 100hr, and wherein the weight hourly throughput is at least 0.001 hr⁻¹. 55.The crystalline molecular sieve recited in claim 54, wherein saidstructure-directing-agent R further comprises R₂, being an amine offormula NR¹R²R³ or a quaternary ammonium compound of formula R¹R²R³R⁴NA,wherein R¹, R², R³, or R⁴, which may be identical or different, eachindependently represent a hydrogen atom, a linear alkyl group havingfrom 1 to 8 carbon atoms, a branched alkyl group having from 3 to 8carbon atoms, or a cycloalkyl group having 5 or 6 carbon atoms, at leastone of R¹, R², R³, and if present R⁴, being other than hydrogen, and Arepresents an anion, wherein the molar ratio of the sum of R₁ and R₂over YO₂ is in the range of from about 0.03 to about 2 and the molarratio of R₁ over YO₂ is in the range of from about 0.015 to about
 2. 56.The crystalline molecular sieve recited in claim 54, wherein the weighthourly throughput is at least 0.008 hr⁻¹.
 57. The crystalline molecularsieve recited in claim 54, wherein said crystallization conditionscomprise a temperature in the range of from about 160° C. to about 200°C., and crystallization time less than 72 hr.
 58. A process forhydrocarbon conversion comprising the step of contacting saidhydrocarbon with a crystalline molecular sieve according to claim 54under hydrocarbon conversion conditions.
 59. The process of claim 58,wherein said crystalline molecular sieve of MFS framework type isZSM-57.